Bluetooth: Destroy BT Dialog on BT power off.

Check for Bluetooth off Broadcast to destroy disconnect
dialog when Bluetooth is turned off from power widget.

Change-Id: Ie556a17c7d574f77da5181c08705648ebf5733cc
CRs-Fixed: 579028
Merge "Bluetooth: Destroy BT Dialog on BT power off." into kk4.4